Trying out the new upgrade functionality on an old 4.8 install -> 7.6.4, and run into a problem:

The database failed to upgrade. ERROR: The database configuration failed with the following message: The index 'IXumbracoNodeUniqueID' is dependent on column 'uniqueID'. ALTER TABLE ALTER COLUMN uniqueID failed because one or more objects access this column. Please check log file for additional information (can be found in '/AppData/Logs/UmbracoTraceLog.txt')

The SQL it is running is:

 2017-07-27 10:39:47,444 [P8764/D14/T22] INFO  Umbraco.Core.Persistence.Migrations.MigrationRunner - Executing sql statement 142: ALTER TABLE [umbracoNode] ALTER COLUMN [uniqueID] UniqueIdentifier NOT NULL

It is incredibly infuriating because it has done loads of the upgrade perfectly, and the column is already a uniqueidentifier so it shouldn't need to run this code anyway!

I don't understand why the migration code earlier creates the index, then tries to modify the column, failing on the index it has just added?

Is there a fix?

P.S. There seems to be a lot of threads about this Unique ID error, with the advice to upgrade to 7.2.3 first; as the new improved upgrader was only put into 7.3, this doesn't seem like it will work here.